# A tibble: 6 × 16
...1 country_region_code country_region sub_region_1 sub_region_2 metro_area
<dbl> <chr> <chr> <chr> <chr> <lgl>
1 9.10e6 US United States <NA> <NA> NA
2 9.10e6 US United States <NA> <NA> NA
3 9.10e6 US United States <NA> <NA> NA
4 9.10e6 US United States <NA> <NA> NA
5 9.10e6 US United States <NA> <NA> NA
6 9.10e6 US United States <NA> <NA> NA
# ℹ 10 more variables: iso_3166_2_code <chr>, census_fips_code <dbl>,
# place_id <chr>, date <date>,
# retail_and_recreation_percent_change_from_baseline <dbl>,
# grocery_and_pharmacy_percent_change_from_baseline <dbl>,
# parks_percent_change_from_baseline <dbl>,
# transit_stations_percent_change_from_baseline <dbl>,
# workplaces_percent_change_from_baseline <dbl>, …
Card, David. 1993. “Using Geographic Variation in College Proximity to Estimate the Return to Schooling.” National Bureau of Economic Research Cambridge, Mass., USA.